UPSC Essentials | Weekly news express with MCQs — Chandrayaan-3, Extreme rainfall, and more

Dear Aspirants,

Thank you for joining us for LIVE sessions. Every day we receive your emails and messages, in large numbers, with queries revolving around news and UPSC preparation in general. Each letter and text makes us feel that we need to do more to simplify your examination preparation journey. You will be happy to know that we will be LIVE every week on Wednesdays, take up your queries, provide you with cues from the news, and discuss a relevant theme revolving around news and UPSC preparation in general. 

You can send your queries at manas.srivastava@indianexpress.com or join Telegram: The Indian Express UPSC Hub or ask me Live! 

Chandrayaan-3

WHY IN NEWS?

— With the launch of Chandrayaan-3 on July 14, the Indian Space Research Organisation (ISRO) is set to make its second attempt to land a spacecraft on the moon. Earlier in 2019, due to problems that had emerged during the last stage of the descent, Chandrayaan-2’s lander and rover crashed on the moon’s surface.

— Should this mission see a successful “soft” landing, India will become only the fourth country – after the United States, Russia, and China – to have done so.

KEY TAKEAWAYS

How do space missions work?

— Any space mission essentially has two parts – the rocket, or the carrier, and the spacecraft, which could be a satellite or any other payload. The rocket has the limited job of transporting the spacecraft into space. In most missions, the rockets get destroyed after completing their job. The spacecraft continues to operate as designed.

— The rocket is powered by a propellant, which is a mix of fuel and oxidisers (that allow for burning to happen), all meant to generate enough energy to help the spacecraft lift-off.

— Once that happens, this powered flight continues and ends only when the rocket’s last stage burns out and the spacecraft separates. The payload should have been, ideally, placed into the orbit of the planetary body that it is supposed to reach by this time.

What was Chandrayaan-1?

— India’s Chandrayaan missions are aimed at lunar exploration, beginning with Chandrayaan-1 that launched on October 22, 2008. “The primary science objective of the mission was to prepare a three dimensional atlas of both near and far side of the Moon and to conduct chemical and mineralogical mapping of the entire lunar surface with high spatial resolution,” ISRO said at the time.

— It made more than 3,400 orbits around the moon and was operational for at least 312 days, until August 29, 2009, when radio contact with the spacecraft was lost.

— However, the fact that it used indigenously developed technology was a major achievement. On November 14, 2008, a payload named MIP (Moon Impact Probe) carried by the spacecraft was separated and it struck the lunar South Pole in a controlled manner. India was then able to make discoveries related to the detection of water (H2O) and hydroxyl (OH) on the lunar surface. The data also revealed their enhanced abundance towards the polar region. It further found ice in the North polar region of the Moon.

What happened with Chandrayaan-2?

— Chandrayaan-2 brought together an Orbiter (to orbit the planetary body and not land on it), Lander (to land on its surface) and Rover (to move on the surface) with the goal of exploring the south pole of the Moon. It was launched in July 2019 and was only a partial success, because on September 7 that year, its lander, Vikram, and rover, Pragyaan, crashed on the Moon’s surface.

— While Vikram was supposed to lose most of its velocity by the time it was 400m from the lunar surface, system errors led to it having a high velocity, resulting in a crash. Nevertheless, its Orbiter functioned well and was able to gather data. It built on the discovery of water from Chandrayaan-1, and found signatures of water at all latitudes.

— The Large Area Soft X-Ray Spectrometer (CLASS), which measures the Moon’s X-ray spectrum to examine the presence of major elements such as magnesium, aluminium, silicon, calcium, titanium, iron, etc., found the minor elements chromium and manganese for the first time through remote sensing.

What does Chandrayaan-3 aim to do?

— Mainly, the Chandrayaan-3 mission is to demonstrate India’s growing technical capabilities in the field and conduct a successful soft landing on the moon.

Amitabha Ghosh, a scientist for NASA’s Rover mission to Mars, explained what this means in The Indian Express thus: “Imagine a spacecraft hurtling through space, at 10 times the speed of an airplane, having to nearly come to a standstill in order to land gently on the Earth — all in a matter of a few minutes and, more importantly, without any human intervention. This, in a nutshell, is a soft landing.”

— The payloads on the lander and rover remain the same as the last mission. There will be four scientific payloads on the lander to study lunar quakes, thermal properties of the lunar surface, changes in the plasma near the surface, and a passive experiment to help accurately measure the distance between Earth and moon. The fourth payload comes from NASA.

— There are two payloads on the rover, designed to study the chemical and mineral composition of the lunar surface and to determine the composition of elements such as magnesium, aluminium and iron in the lunar soil and rocks.

— Notably, the landing site of the latest mission is more or less the same as the Chandrayaan-2: near the south pole of the moon at 70 degrees latitude. If everything goes well, the Chandrayaan-3 will become the world’s first mission to soft-land near the lunar south pole.

Why will it take so many days for the lander to reach the moon?

— This whole process is likely to take around 42 days, with the landing slated for August 23 at the lunar dawn.

— The Chandrayaan-3 mission will be launched into space by the Launch Vehicle Mark-III, (LVM-III). After launching into an orbit around the Earth at an altitude of 179 km on Friday, the spacecraft will gradually increase its orbit in a series of manoeuvres to escape the Earth’s gravity and slingshot towards the moon. After reaching close to the moon, the spacecraft will need to be captured by its gravity.

(This ISRO illustration shows how a payload, in this case Chandrayaan-3, reaches its destination, from earth to space.)

— Once that happens, another series of manoeuvres will reduce the orbit of the spacecraft to a 100×100 km circular one. Thereafter, the lander, which carries the rover inside it, will separate from the propulsion module and start its powered descent towards the moon’s surface.

— The craft lander and rover have a mission life of one Lunar day. Each Lunar day lasts for 14 earth days, as does each Lunar night, as it takes around one month (close to 28 earth days) for the moon to complete one rotation on its axis (and one revolution around the earth). The rover and lander cannot survive the extreme drop in temperatures during lunar nights, which is why they are being landed right at dawn.

Why is it so difficult to land on the Moon?

1) Getting to the Moon

— Long before you can even think of landing on the Moon, you will have to figure out how to get there. On an average, the Moon is about 3,84,400 kilometres away from our planet and depending on the path taken by the spacecraft, that distance can be much higher. A failure can occur anywhere on this long, long journey.

— And that is true even for missions that just want to travel the Moon without landing. NASA had to terminate the Lunar Flashlight mission because a failure in the spacecraft’s propulsion system meant that it could not enter the lunar orbit.

2) Slowing down on the Moon

— Spacecraft returning back to our planet, like NASA’s Orion after the Artemis 1 mission, can rely on the Earth’s thick atmosphere providing enough friction to slow down before touching down safely. But spacecraft entering the Moon do not have that luxury because of its extremely thin atmosphere.

— In such a scenario, the only thing that can slow down a spacecraft is its propulsion system. This means that it will have to carry a lot of fuel just so that it has enough to slow itself down quickly enough to make a safe landing. But carrying more fuel means the spacecraft is heavier, requiring more fuel. This problem is a bit similar to what is known as the “Tyranny of the Rocket Equation.”

3) Navigating on the Moon

— Needless to say, there is no GPS on the Moon. Spacecraft cannot rely on a network of satellites to precisely land at a particular location because that simply does not exist on the Moon. This means that onboard computers will have to make quick calculations and decisions to land itself precisely on the Moon.

— This becomes especially complicated when a spacecraft gets within the crucial last few kilometres, according to a report in the journal, Nature . At that point, the computers on board will have to autonomously react quickly to last-minute issues. For example, sensors could become confused by the large amounts of dust kicked up by the propulsion systems.

— This is made even more difficult by the fact that the Moon has an uneven surface littered with craters and boulders. Landing on either could prove catastrophic for the mission.

Why do we want to go to the moon?

— The Moon is the closest cosmic body to earth, where space discovery can be attempted and documented, said ISRO at the time of Chandrayaan-2. It was also described as a promising test bed to demonstrate technologies required for future deep-space missions.

— There are two payloads on the rover, designed to study the chemical and mineral composition of the lunar surface and to determine the composition of elements such as magnesium, aluminium and iron in the lunar soil and rocks.

— Notably, the landing site of the latest mission is more or less the same as the Chandrayaan-2: near the south pole of the moon at 70 degrees latitude. If everything goes well, the Chandrayaan-3 will become the world’s first mission to soft-land near the lunar south pole.

Why land near the south pole?

— As NASA says, “Extreme, contrasting conditions make it a challenging location for Earthlings to land, live, and work, but the region’s unique characteristics hold promise for unprecedented deep space scientific discoveries.”

— All spacecraft that have landed on the Moon so far have landed near its equator. This is because both the terrain and conditions are more hospitable there. The polar regions present a much more difficult terrain to carry out lunar missions.

— The extremely cold temperatures in the polar region mean that it can act as a kind of “time capsule” where things do not undergo much change. The rocks and soil there could give scientists clues about the origin of the solar system. There is also a chance of detecting water ice in that part of the Moon.

— NASA noted the importance of Lunar polar volatiles. Volatiles are chemical elements or compounds in a solid state that melt or evaporate at moderately warm temperatures and can be found on the moon. Space missions could help understand their distribution on the moon. If they contain elements like Hydrogen and Oxygen, this “could have a profound impact on the future of deep space exploration and commerce”, NASA says. It would reduce the amount of supplies that would have to be sent from Earth to support humans in deep space.

How did Sriharikota become India’s launchpad?

— One main consideration that played in its favour, is the fact that it is on the eastern coast which makes it easier to launch rockets to the East. Rockets are typically launched in the eastern direction because then, they get a boost of momentum from Earth’s rotation. The other main consideration is the fact that it is close to the equator. Rockets launched from the equator can take maximum advantage from the Earth’s rotation.

— Of course, other considerations like the fact that Sriharikota was a sparsely populated region close to the sea also played into this decision.

What else you should know?

— LVM3 (Launch Vehicle Mark-III), which carried the Chandrayaan-3 spacecraft into Earth’s orbit, went through more than 3,000 wind tunnel tests at the Council of Scientific & Industrial Research-National Aerospace Laboratories (CSIR-NAL) facilities in Bengaluru. These tests helped mission scientists understand more about the aerodynamics of the rocket and how air will flow around it when it is in flight.

— The Chandrayaan-3 mission is almost identical to the Chandrayaan-2 mission, which ended in failure during its last legs a the Vikram lander crash landed on the Moon’s surface. But there are some important new upgrades that ISRO is hoping will give the new mission an edge over its predecessor. This includes some upgrades to the lander—a bigger fuel tank, solar panels on all four sides instead of just two, updated software, additional strength tests, and more. Additional navigational and guidance instruments are on board Chandrayaan-3 to continuously monitor the Lander’s speed, and make the necessary corrections. This includes an instrument called Laser Doppler Velocimeter, which will fire laser beams to the lunar surface to calculate the Lander’s speed. New sensors and cameras have also been added.

(Sources: CHANDRAYAAN 3)

Point to ponder: The Chandrayaan and Mangalyaan missions are signals that the coming of age of India’s space programme, a shift in strategy, and a stepping stone to much bigger things in space travel and exploration. Discuss.

1. MCQ: 

With reference to Chandrayaan Missions, consider the following statements:

1. With it India is hoping to be the fourth nation after the US, the Soviet Union, and EU to achieve a soft landing on the Moon.

2. The mission will likely be the first to conduct a sampling of Moon ice. 

3. While Chandrayaan-2 comprised a lander and rover – Vikram and Pragyan respectively, the Chandrayaan-3 will use an orbiter already hovering over the Moon that was launched with Chandrayaan-2 for its communications and other support for terrain mapping.

Which of the above statement(s) is/are not true?

(a) Only 1

(b) Only 2

(c) Only 3

(d) 1 and 3 only

Extreme Rainfall

WHY IN NEWS?

— Northern India was currently in the midst of an extremely wet phase of the monsoon.

— The monsoon season this year was not expected to be very wet. The start certainly wasn’t that great, and notwithstanding the reassuring predictions of a normal monsoon by India Meteorological Department, rains were expected to be suppressed by a developing El Nino.

KEY TAKEAWAYS

Amitabh Sinha Explains:

North badly hit